Eva

Brad: "I heard that you're a half-breed, born from a union of a human and a demon. If that's so, can you tell me: were your parents in love? Was there a love between human and demon?" Dante: "Who knows. Here is your stories about the lovers: they look like they were made for each other, but inside their hearts are as cold as ice." Brad: "That's not that..." Dante: "...But, I think a lot of those couples truly loved each other, deep inside their hearts." — ''Devil May Cry: The Animated Series

Eva was the human wife of Sparda and mother of the twins Vergil and the series main protagonist Dante.

History
Little is known about Eva. She herself appears only as a photo on Dante's desk and as a voice in a flashback in the first Devil May Cry game. What is known is that some time before their 8th birthday, she gave each of the boys half of Sparda's amulet and that she was killed in a demon attack, implied to have been ordered by Mundus. While the exact details of that terrible event were never revealed, it seems that she gave her life for her sons. Eva's death is most likely the event that shaped the paths Dante and Vergil took, causing Dante to fight demons and Vergil to search for Force Edge.

Some other example, showing how important was her figure in the minds of her sons, particularly the youngest one, is that Trish was made by Mundus to look like Eva in order to manipulate Dante. This influence was most clearly seen when Trish was saved by Dante despite her already showing her true colors. However, Dante comments that "you have her face, but you'll never have her fire." Yet, although he said that "Next time, it won't be like this," he later saves her life again, nearly at the cost of his own.